31669638 has 64 divisors (see below), whose sum is σ = 85059072. Its totient is φ = 7591680.

The previous prime is 31669633. The next prime is 31669697. The reversal of 31669638 is 83696613.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 31669638.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31669633) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3370 + ... + 8642.

It is an arithmetic number, because the mean of its divisors is an integer number (1329048).

Almost surely, 2^31669638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31669638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42529536).

31669638 is an abundant number, since it is smaller than the sum of its proper divisors (53389434).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31669638 is a wasteful number, since it uses less digits than its factorization.

31669638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5309.

The product of its digits is 139968, while the sum is 42.

The square root of 31669638 is about 5627.5783424134. The cubic root of 31669638 is about 316.3838935821.

The spelling of 31669638 in words is "thirty-one million, six hundred sixty-nine thousand, six hundred thirty-eight".